{"problem":{"name":"素数对","description":{"content":"定义两个相差为 $2$ 的素数称为素数对，如 $5$ 和 $7,17$ 和 $19$ 等，要求找出所有两个数均不大于 $n$ 的素数对。","description_type":"Markdown"},"platform":"Luogu","limit":{"time_limit":1000,"memory_limit":131072},"difficulty":{"LuoguStyle":"P1"},"is_remote":true,"is_sync":true,"sync_url":null,"sign":"LGB2132"},"statements":[{"statement_type":"Markdown","content":"定义两个相差为 $2$ 的素数称为素数对，如 $5$ 和 $7,17$ 和 $19$ 等，要求找出所有两个数均不大于 $n$ 的素数对。\n\n## Input\n\n一个正整数 $n$。$1 \\le n \\le 10000$。\n\n## Output\n\n所有小于等于 $n$ 的素数对。每对素数对输出一行，中间用单个空格隔开。若没有找到任何素数对，输出 `empty`。\n\n[samples]","is_translate":false,"language":"English"}],"meta":{"iden":"LGB2132","tags":["函数与递归"],"sample_group":[["10","3 5\n5 7"],["100","3 5\n5 7\n11 13\n17 19\n29 31\n41 43\n59 61\n71 73"],["3","empty"]],"created_at":"2026-03-03 11:09:25"}}